RETRO-MAPPING: A New Approach to Activation Mapping in Persistent Atrial Fibrillation Reveals Evidence of Spatiotemporal Stability

2021 ◽  
Author(s):  
Ian Mann ◽  
Nick W.F. Linton ◽  
Clare Coyle ◽  
James P. Howard ◽  
Michael Fudge ◽  
...  
Keyword(s):  
Time Windows ◽  
Persistent Atrial Fibrillation ◽  
Activation Patterns ◽  
New Approach ◽  
Af Ablation ◽  
Mapping Software ◽  
Collection Data ◽  
Consecutive Time ◽  
Activation Mapping ◽  
Total Activation

Background - The mechanisms underlying AF remain controversial. We developed RETRO-Mapping to characterize activation wavefronts by direction and uniformity, accumulating data as an orbital plot and analyzed as frequency histograms. We applied this technique to patients undergoing AF ablation to determine if AF activation is random. Methods - Patients undergoing persistent AF ablation were recruited and an AFocusII was positioned at multiple left atrial locations and kept steady for 1min to collect electrograms. The AFocusII was returned to the original site and position after >10mins for a repeat 1min data collection. Data was exported to custom RETRO-Mapping software, and 30sec consecutive time windows at each location were studied using frequency histograms of wavefronts. R50 (the range in degrees containing 50% of the total activation) was used as a method to enable statistical comparisons of activation patterns. Electrogram characterization into categories of complex fractionated atrial electrograms (CFAEs) by Ensite Precision was subjected to similar analysis. Results - Consecutive 30secs segments were studied at 161 locations in 18pts. Mean overlap between frequency histograms was 79.5%±7.7 (95%CI 78.3 to 80.7). 9 patients underwent delayed mapping at the same location, and mean overlap between the first 30sec and >10min interval was 73%±11.8 and 71.9%±13.6 for consecutive 30sec segments. Stability was confirmed using R50 (Bland-Altman mean difference: 0.87; LOA: -34.0 to 36.0; r=0.005; P=0.95). A greater variance in R50 was observed between different locations within a patient than the variance within the same locations (ICC=0.765; p<0.0001), and similarly for both CFAE and bipolar voltage (P<0.0001). A larger area containing CFAE (80-120ms) showed weak positive correlation with increasing R50 (r = 0.36, P<0.001) suggesting a relationship between activation pattern and electrogram characteristics. Conclusions - There appears to be preferential activation patterns during persistent AF indicating spatiotemporal stability. This has important implication to our mechanistic understanding of persistent AF.

scholarly journals Endocardial-Epicardial Phase Mapping of Prolonged Persistent Atrial Fibrillation Recordings

2020 ◽  
Vol 13 (8) ◽  
Author(s):  
Ramanathan Parameswaran ◽  
Jonathan M. Kalman ◽  
Alistair Royse ◽  
John Goldblatt ◽  
Marco Larobina ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Persistent Atrial Fibrillation ◽  
Temporal Heterogeneity ◽  
Activation Patterns ◽  
3 Dimensional ◽  
Transmural Migration ◽  
Endocardial Mapping ◽  
Phase Mapping ◽  
Insight Into ◽  
Activation Mapping

Background: Endocardial-epicardial dissociation and focal breakthroughs in humans with atrial fibrillation (AF) have been recently demonstrated using activation mapping of short 10-second AF segments. In the current study, we used simultaneous endo-epi phase mapping to characterize endo-epi activation patterns on long segments of human persistent AF. Methods: Simultaneous intraoperative mapping of endo- and epicardial lateral right atrium wall was performed in patients with persistent AF using 2 high-density grid catheters (16 electrodes, 3 mm spacing). Filtered unipolar and bipolar electrograms of continuous 2-minute AF recordings and electrodes locations were exported for phase analyses. We defined endocardial-epicardial dissociation as phase difference of ≥20 ms between paired endo-epi electrodes. Wavefronts were classified as rotations, single wavefronts, focal waves, or disorganized activity as per standard criteria. Endo-Epi wavefront patterns were simultaneously compared on dynamic phase maps. Complex fractionated electrograms were defined as bipolar electrograms with ≥5 directional changes occupying at least 70% of sample duration. Results: Fourteen patients with persistent AF undergoing cardiac surgery were included. Endocardial-epicardial dissociation was seen in 50.3% of phase maps with significant temporal heterogeneity. Disorganized activity (Endo: 41.3% versus Epi: 46.8%, P =0.0194) and single wavefronts (Endo: 31.3% versus Epi: 28.1%, P =0.129) were the dominant patterns. Transient rotations (Endo: 22% versus Epi: 19.2%, P =0.169; mean duration: 590±140 ms) and nonsustained focal waves (Endo: 1.2% versus Epi: 1.6%, P =0.669) were also observed. Apparent transmural migration of rotational activations (n=6) from the epi- to the endocardium was seen in 2 patients. Electrogram fractionation was significantly higher in the epicardium than endocardium (61.2% versus 51.6%, P <0.0001). Conclusions: Simultaneous endo-epi phase mapping of prolonged human persistent AF recordings shows significant Endocardial-epicardial dissociation marked temporal heterogeneity, discordant and transitioning wavefronts patterns and complex fractionations. No sustained focal activity was observed. Such complex 3-dimensional interactions provide insight into why endocardial mapping alone may not fully characterize the AF mechanism and why endocardial ablation may not be sufficient. Graphic Abstract: A graphic abstract is available for this article.

scholarly journals A Novel Deep Learning Approach for Machinery Prognostics Based on Time Windows

2019 ◽  
Vol 9 (22) ◽  
pp. 4813 ◽  
Author(s):  
Hanbo Yang ◽  
Fei Zhao ◽  
Gedong Jiang ◽  
Zheng Sun ◽  
Xuesong Mei
Keyword(s):  
Time Windows ◽  
Remaining Useful Life ◽  
Sensor Data ◽  
Time Interval ◽  
Kernel Module ◽  
Initial Stage ◽  
Research Task ◽  
Consecutive Time ◽  
Useful Life

Remaining useful life (RUL) prediction is a challenging research task in prognostics and receives extensive attention from academia to industry. This paper proposes a novel deep convolutional neural network (CNN) for RUL prediction. Unlike health indicator-based methods which require the long-term tracking of sensor data from the initial stage, the proposed network aims to utilize data from consecutive time samples at any time interval for RUL prediction. Additionally, a new kernel module for prognostics is designed where the kernels are selected automatically, which can further enhance the feature extraction ability of the network. The effectiveness of the proposed network is validated using the C-MAPSS dataset for aircraft engines provided by NASA. Compared with the state-of-the-art results on the same dataset, the prediction results demonstrate the superiority of the proposed network.

Abstract 18957: Modulation of Ganglionated Plexi as an Addition to Pv Isolation in Persistent Atrial Fibrillation Ablation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Sabine Ernst ◽  
Richard Underwood ◽  
Sonya Babu-Narayan ◽  
Simona Ben-Haim
Keyword(s):  
Atrial Fibrillation ◽  
3D Imaging ◽  
Imaging Study ◽  
Persistent Atrial Fibrillation ◽  
High Frequency Stimulation ◽  
Af Ablation ◽  
Road Map ◽  
Ganglionated Plexi ◽  
Individual Variations ◽  
Frequency Stimulation

Introduction: Catheter ablation of ganglionated plexi (GP) as an add on to pulmonary vein (PV) isolation has been reported to significantly improve outcome of atrial fibrillation (AF) ablation. In order to facilitate localization of these GPs, a novel imaging study is proposed that investigates the uptake of iodine-123 metaiodobenzylguanidine (mIBG, an analogon for norepinephrine) on the atrial level. This information is combined with 3D surface reconstruction from contrast computed tomography (cCT) or cardiac magnetic resonance (CMR). Methods: A total of 7 patients (5 male, mean age 64.3 yrs) with AF underwent mIBG nuclear studies using a dedicated solid state cardiac camera (D-SPECT, Spectrum Dynamics). Four patient had 4 persistent AF (3 prev. abl.) with less than 1 year of sustained AF, whereas 3 patient were in longstanding persistent AF (all prev. abl). The acquired data was merged with the 3D imaging and subsequently imported into the 3D electroanatomical mapping system (CARTO, Biosense Webster). During invasive AF ablations these sites were mapped to perform high frequency stimulation (HFS) to confirm GP locations. Results: In all pts, both the mIBG and CT scans were performed without any complications. Locations of high mIBG uptake corresponded to anatomical GP sites (LA & RA) in the majority of patients, but individual variations were observed. PV isolation was added in all but 1 pt (who had previous ablation) plus CFAE ablation if necessary. Follow-up of in median of 10.4 months demonstrated SR in all persistent AF patients (1 redo for atrial reentry). In patients with longstanding persistent AF: 2 pts are in SR (both AF at 1 week and 1 pt in AT at 6 weeks), while 1 pt remained in AF. Conclusion: The combination of mIBG and 3D imaging provides a novel type of “road map” for localizing GPs during AF ablation. As an add-on to PV (re-) isolation, this strategy was found to be beneficial for patients with persistent and longstanding persistent AF. Interestingly, pts with longstanding persistent AF (and multiple previous ablations) all recurred early in F/U but showed reversal to AT and finally SR at later stages. Further studies in larger patient cohorts need to confirm these initial observations.

Abstract 15934: Comparison of Atrial Fibrillation Burden Reduction in Patients With Paroxysmal and Persistent Atrial Fibrillation Undergoing Cryoballoon Pulmonary Vein Isolation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Dan L Musat ◽  
Nicolle S Milstein ◽  
Jacqueline Pimienta ◽  
Advay Bhatt ◽  
Tina C Sichrovsky ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Vein ◽  
Pulmonary Vein Isolation ◽  
Persistent Atrial Fibrillation ◽  
Loop Recorder ◽  
Similar Reduction ◽  
Af Ablation ◽  
Ablation Success ◽  
One Year ◽  
Af Recurrence

Background: Pulmonary vein isolation (PVI) is a cornerstone of atrial fibrillation (AF) ablation procedures to treat symptomatic AF. Ablation success is defined by absence of AF recurrence >30 seconds. However, reduction in AF burden (AFB) is also an important endpoint. Whether patients with paroxysmal (PAF) and persistent AF (PeAF) have similar reduction in AFB post-ablation is unknown. Objective: To compare the decrease in AFB following cryoballoon (CB) PVI in patients with PAF and PeAF. Methods: We enrolled consecutive pts with an implantable loop recorder (ILR) who subsequently underwent CB PVI. All patients were followed prospectively for at least one year, or until repeat ablation; we compared AFB pre and post-ablation. Results: The cohort included had 47 patients (66 ± 10 years; 32 [68%] male; PAF [n=23, 49%]; CHA 2 DS 2 -VASc 2.7 ± 1.7, 34 [72%] on AAD at the time of ablation). A median of 136 days [IQR 280, 73; minimum of 30 days] of ILR data pre-ablation were available. The median AFB for PAF was 4.7% [IQR 0.9, 14.8] and PeAF was 6.8% [IQR 1.1, 40.4]. After excluding a 3-month post-ablation blanking period, recurrent AF occurred in 12 (52%) PAF and 11 (46%) PeAF patients. The median AFB post-ablation for PAF and PeAF cohorts was 0.03%, [IQR 0, 0.3] and 0.04%, [IQR 0, 1.1], respectively. This represents a >99% reduction in AFB. Conclusion: Although 50% of patients undergoing CB PVI for PAF or PeAF had a recurrence of AF, there was >99% reduction in AFB in both groups. These data highlight the importance of using AFB burden as a marker of therapeutic efficacy post-AF ablation.

scholarly journals Activeness and Loyalty Analysis in Event-Based Social Networks

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 119
Author(s):  
Thanh Trinh ◽  
Dingming Wu ◽  
Joshua Zhexue Huang ◽  
Muhammad Azhar
Keyword(s):  
Social Networks ◽  
Online Social Networks ◽  
Time Windows ◽  
Social Groups ◽  
Time Frame ◽  
Machine Learning Techniques ◽  
Consecutive Time ◽  
Highly Correlated ◽  
Event Based ◽  
Association Matrix

Event-based social networks (EBSNs) are widely used to create online social groups and organize offline events for users. Activeness and loyalty are crucial characteristics of these online social groups in terms of determining the growth or inactiveness of the social groups in a specific time frame. However, there is less research on these concepts to clarify the existence of groups in event-based social networks. In this paper, we study the problem of group activeness and user loyalty to provide a novel insight into online social networks. First, we analyze the structure of EBSNs and generate features from the crawled datasets. Second, we define the concepts of group activeness and user loyalty based on a series of time windows, and propose a method to measure the group activeness. In this proposed method, we first compute a ratio of a number of events between two consecutive time windows. We then develop an association matrix to assign the activeness label for each group after several consecutive time windows. Similarly, we measure the user loyalty in terms of attended events gathered in time windows and treat loyalty as a contributive feature of the group activeness. Finally, three well-known machine learning techniques are used to verify the activeness label and to generate features for each group. As a consequence, we also find a small group of features that are highly correlated and result in higher accuracy as compared to the whole features.

Identification of repetitive atrial activation patterns in persistent atrial fibrillation by direct contact high‐density electrogram mapping

2019 ◽  
Vol 30 (12) ◽  
pp. 2704-2712 ◽  
Author(s):  
Michael Wolf ◽  
René Tavernier ◽  
Ziad Zeidan ◽  
Milad El Haddad ◽  
Yves Vandekerckhove ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Direct Contact ◽  
Persistent Atrial Fibrillation ◽  
High Density ◽  
Activation Patterns ◽  
Atrial Activation

scholarly journals Differences in Healthcare Use Between Patients With Persistent and Paroxysmal Atrial Fibrillation Undergoing Catheter‐Based Atrial Fibrillation Ablation: A Population‐Based Cohort Study From Ontario, Canada

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Andrew C. T. Ha ◽  
Harindra C. Wijeysundera ◽  
Feng Qiu ◽  
Kayley Henning ◽  
Kamran Ahmad ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Emergency Room ◽  
Persistent Atrial Fibrillation ◽  
Population Based ◽  
Adverse Outcomes ◽  
Administrative Databases ◽  
Emergency Room Visits ◽  
Success Rates ◽  
Healthcare Use ◽  
Af Ablation

Background Patients with persistent atrial fibrillation (AF) undergoing catheter‐based AF ablation have lower success rates than those with paroxysmal AF. We compared healthcare use and clinical outcomes between patients according to their AF subtypes. Methods and Results Consecutive patients undergoing AF ablation were prospectively identified from a population‐based registry in Ontario, Canada. Via linkage with administrative databases, we performed a retrospective analysis comparing the following outcomes between patients with persistent and paroxysmal AF: healthcare use (defined as AF‐related hospitalizations/emergency room visits), periprocedural complications, and mortality. Multivariable Poisson modeling was performed to compare the rates of AF‐related and all‐cause hospitalizations/emergency room visits in the year before versus after ablation. Between April 2012 and March 2016, there were 3768 consecutive patients who underwent first‐time AF ablation, of whom 1040 (27.6%) had persistent AF. The mean follow‐up was 1329 days. Patients with persistent AF had higher risk of AF‐related hospitalization/emergency room visits (hazard ratio [HR], 1.21; 95% CI, 1.09–1.34), mortality (HR, 1.74; 95% CI, 1.15–2.63), and periprocedural complications (odds ratio, 1.36; 95% CI, 1.02–1.75) than those with paroxysmal AF. In the overall cohort, there was a 48% reduction in the rate of AF‐related hospitalization/emergency room visits in the year after versus before ablation (rate ratio [RR], 0.52; 95% CI, 0.48–0.56). This reduction was observed for patients with paroxysmal (RR, 0.45; 95% CI, 0.41–0.50) and persistent (RR, 0.74; 95% CI, 0.63–0.87) AF. Conclusions Although patients with persistent AF had higher risk of adverse outcomes than those with paroxysmal AF, ablation was associated with a favorable reduction in downstream AF‐related healthcare use, irrespective of AF type.

scholarly journals Illuminating the Marshall: novel techniques highlighted in an atrial tachycardia case report

2020 ◽  
Vol 4 (4) ◽  
pp. 1-5
Author(s):  
Renato Margato ◽  
Konstantinos Tampakis ◽  
Jean Paul Albenque ◽  
Stephane Combes
Keyword(s):  
High Density ◽  
Af Ablation ◽  
Density Mapping ◽  
Ethanol Infusion ◽  
Mapping Software ◽  
Precise Diagnosis ◽  
History Of ◽  
Activation Map ◽  
Mapping Systems

Abstract Background Electroanatomic mapping is usually required in order to obtain a precise diagnosis and guide the ablation of atrial tachycardias (ATs) after ablation for atrial fibrillation (AF). However, epicardial connections may limit the interpretation of the endocardial activation sequence as well as the efficacy of endocardial radiofrequency ablation. Case summary A 53-year-old man with history of AF ablation 2 years ago was admitted for ablation of a recurrent AT (cycle length 275 ms). Ultra-high-density mapping with the Rhythmia™ system revealed a challenging activation map with two focal points of early activation in the left atrium. The use of an advanced mapping software allowed the rapid reanalysis and reannotation of the activation map and suggested epicardial involvement of the Marshall bundle (MB). Subsequent ethanol infusion in the vein of Marshall (VOM) immediately terminated the tachycardia. Six months post-ablation, the patient had no recurrence of arrhythmias. Discussion This case highlights the role of novel diagnostic and treatment methods in the management of a post-AF ablation AT. By developments in cardiac mapping systems, the rapid editing of a high-density activation map and clarification of the arrhythmia origin can be facilitated overcoming the limitations of conventional techniques. Moreover, ethanol infusion in the VOM was shown to be an effective alternative method in the management of MB-related tachycardias.

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